Water jet for a speed boat

ABSTRACT

In a water jet drive mounted inboard in a speed boat, a drive shaft drives an impeller shaft over a bevel gear drive within a stator housing. Both the drive shaft and the impeller shafts are rotatably mounted in a pair of spaced bearings within the stator housing, the bearings for each of the shafts are located each on an opposite side of the beveled gear drive.

United States Patent [191 Elger 1 Sept. 23, 1975 WATER JET FOR A SPEEDBOAT [75] Inventor: Gerd Elger, Winterthur, Switzerland [73] Assignee:Allianz-Technik AG, Basel,

Switzerland [22] Filed: Jan. 14, 1974 [21] Appl. No.: 433,293

[52] [1.5. Cl. 115/16; 115/42; 60/221 [51] Int. C1. B63I-I 11/02 [58]Field of Search l15/1l,14,16, 42, 34 R;

[56] References Cited UNITED STATES PATENTS 3,044,260 7/1962 Hamilton115/16 FOREIGN PATENTS OR APPLICATIONS France 115/34 R 1,189,779 4/1970Canada 114/151 Primary Examiner-Trygve M. Blix Assistant ExaminerShermanD. Basinger Attorney, Agent, or Firm-Toren, McGeady and Stanger [57]ABSTRACT In a water jet drive mounted inboard in a speed boat, a driveshaft drives an impeller shaft over a bevel gear drive within a statorhousing. Both the drive shaft and the impeller shafts are rotatablymounted in a pair of spaced bearings within the stator housing, thebearings for each of the shafts are located each on an opposite side ofthe beveled gear drive.

2 Claims, 3 Drawing Figures US Patent Sept. 23,1975 Sheet 1 of23,906,886

FIG!

WATER JET FOR A SPEED BOAT SUMMARY OF THE INVENTION .a relatively longstator housing. As, in addition, the

shaft of the driving bevel gear must pass outside the stator housingboth the design and manufacture of the stator housing becomecomplicated. Furthermore, a guidance device is required in order tocorrectly guide the current paths of the water accelerated by theimpeller. The housing and guidance device lead to an elongatedconstruction. Quite apart from the high material and manufacturingcosts, a long housing is also disadvantageous in that the area wetted bythe water becomes relatively. large which increases the flow resistance,and, therefore, unfavourably influences the efficiency.

The problem of the invention -is to construct a water jet drive of theabove-mentioned type so that the stator housing and its impeller shaftas well as the guidance device is shorter and lighter than in the past,so that the area to be wetted by the water is smaller and consequentlythe efficiency of the water jet drive rises, that the introduction ofthe axial thrust into the stator housing takes place in the shortestmanner thereby increasing the lifeof the water jet drive and thatfinally its material andmanufacturing costs are reduced.

According to the invention, this problem is solved in that the impellershaft bearings are arranged inside the stator housing on both sides ofthe bevel gear drive and the stator housing is constructed as a guidancedevice.

In this surprisingly simple manner it ispossible to make the water jetdrive about 40% shorter than in the past and to construct the housingand guidance device as one casting. As the bevel gear drive is enclosedby bearings the overhung mounting becomes superfluous, the impellershaft becomes shorter and its bending load is greatly reduced.. Due tothe smaller wettable surface area the .flow losses in the guidancedevice areconsiderably reduced and,.as a result, the efficiency isincreased. The shorter construction not only affords more space in theboat but also, due to the possibility of placing the water intakefurther aft, the dangerous sucking in of air which has previously alwaysoccurred at high speeds, is prevented. The shorter and more compactconstruction also permits rational construction and saves material andweight.

According to a preferred embodiment, the pumpside. bearing is placed inthe stator housing by means of a one-part bearing flange, while thebearing remote from the flow is placed directly thereinand the end ofthe stator housing remote from the flow is covered by a twopartbell-like member.

The bell-like member comprises two bell domes, one arrangedconcentrically to the other, whereby the inner bell dome is detachablyfixed to the stator housing and the outer bell dome is detachably fixedto a central extension of the inner bell dome.

According to a further feature of the invention, the driving bevel gearis also rotatably supported in two spaced locations, whereby the firsthearing is located in i an attachment on the outer casing and the secondbearing in the stator housing projection projecting into the bearingframe of the bevel gear drive, so that, once again the overhung mountingis avoided.

To permit access to the bearing box of the bevel gear drive inside thestator housing the latter has an opening opposite the attachment of theouter casing for receiv ing one of the bearings of the driving bevelgear which can be sealed by an insert having the cross-sectional shapeof the stator housing.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which there is illustrated and described a preferredembodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic showing ofaportion of a speed board containing the water jet drive of the presentinvention;

FIG. 2 is a cross-section through the set of pumps of a water jet driveaccording to the invention, and

DETAILED DESCRIPTION OF THE INVENTION includes a rotor or impeller 4(FIG. 2) fixed to a horizontal impeller shaft 5 rotatably mounted in thesocalled stator housing 8 by means of two spaced bearings 6 and 7.Between the bearings, in the form of ball bearings, is positioned abevel gear drive 9 having a driver bevel gear 10 located on the impellershaft. The

driving bevel gear. 11 of the gear drive isfixed to a drive.

shaft 12 extending perpendicularly to the impeller shaft 5. The driveshaft 12 is also rotatably mounted in stator housing 8 by means of twospaced bearings 13 and 14, in the form of ball bearings with bearing 13arranged in a projection 14 on the bearing frame 16 and bearing 14 in anattachment on the outer surface of the stator housing. Driver bevel gear10 and bearing 13 are 10- cated in the bearing frame 16 of the statorhousing 8 which is sealed all round against entry of water.

The pump-side bearing 6, located adjacent to the impellcr, is arrangedby means of a bearing flange 17 in a front end opening 18 and bearing 7remote from the impeller is arranged directly in a front end opening 19of the stator housing. A springloaded sealing ring 20 seals the bearingpoint of bearing 6 against the entry of water.

The front end opening 19 remote from the impeller is covered by atwopart bell-like member 22 which comprises two concentrically arrangedbell domes 23 and 24. The inner bell dome 23 is fixed to the projection25 on the end of the stator housing remote from the impeller by means ofscrews 26 and the outer bell FIG. 3 is a section following the line llII of FIG. I

dome 24 is fixed by a screw 27 to a central extension 28 of the innerbell dome and is supported via a bead 29 on its wide end on the statorhousing. Sealing ring 32 seals the bearing and therefore also bearingframe 16 against the penetration of water.

In order, during assembly of the perpendicular drive shaft 12, to beable to insert bearing 13 into bearing frame 16, an opening 35 isprovided in stator housing 8 which is scalable in water-tight manner byan insert 36 which has in cross-section the shape of the stator housingat this point.

The stator housing 8 itself is in the form of an inner shell 37 and anouter shell 38 spaced apart to form a partitioned duct 40 which servesas a guidance device. The duct 40 is partly interrupted only in the areaof the inlet 41 of drive shaft 12. lnlet 41 is sealed in watertightmanner with the aid of sealing ring 42 and cover plate 43.

An intake 44 is attached to the impeller end of the stator housing andan outlet 45 is attached to its opposite end,

As can be gathered from the above. the described water jet drive isextremely short and compact and the stator housing with the guidancedevice represents only a single casting. Thus, in this case theadvantage of a short pump is not lost as a result of the disadvantage ofa very long pump/motor construction.

While a specific embodiment of the invention has been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

I claim:

l. A water jet drive mounted inboard in a speed boat which has a waterinlet in the bottom of the boat and a jet nozzle outlet in the stern ofthe boat, comprising a stator housing positioned in the boat and formingan annular flow passage and having an inlet end connected to the waterinlet into the boat and an outlet end connected to the jet nozzle outletfrom the boat, a drive shaft arranged to be driven by a motor mounted inthe boat and said drive shaft extending into said stator housing, adriving bevel gear mounted on said drive shaft within said statorhousing, an impeller shaft mounted in said stator housing and extendingin the direction of flow between the inlet end and the outlet end ofsaid stator housing, a driver bevel gear positioned on said impellershaft and arranged to be driven by said driving bevel gear, wherein theimprovement comprises first bearing means provided within said statorhousing for rotatably supporting said impeller shaft and second bearingmeans provided within said stator housing for rotatably supporting saiddrive shaft, said first bearing means comprises a pair of spaced firstbearing mem bers mounted on said impeller shaft, each on an oppositeside of said driver bevel gear, and said second bearing means comprisesa pair of second bearing members mounted on said drive shaft, each on anopposite side of said driving bevel gear, said stator housing comprisesan annular-shaped inner shell and an annular-shaped outer shellencircling and spaced outwardly from said inner shell, said inner andouter shells defining therebetween an annular flow passage through saidstator housing, said inner shell having a first end directed toward theinlet end of said stator housing, and a second end directed toward theoutlet end of said stator housing, said impeller shaft extending throughthe first end of said inner shell, an impeller mounted on said impellershaft between the inlet end of said stator housing and the first end ofsaid inner shell, a bearing flange mounted in the first end of saidinner shell, one of said first bearing members supported in said bearingflange, the other one of said first bearing members supported directlyin the second end of said inner shell, a two-part bell-like memberattached to the second end of said inner shell and forming a closureover the second end of said inner shell, said two-part bell-like membercomprises an inner bell dome attached to the second end of said innershell and projecting therefrom toward the outlet end of said innerhousing, said inner bell dome having a centrally positioned extensionextending toward the outlet end of said stator housing, and an outerbell dome concentrically arranged about said inner bell dome anddetachably secured to said centrally positioned extension on said innerbell dome.

2. A water jet drive mounted inboard in a speed boat which has a waterinlet in the bottom of the boat and a jet nozzle outlet in the stern ofthe boat, comprising a stator housing positioned in the boat and formingan annular flow passage and having an inlet end connected to the waterinlet into the boat and an outlet end connected to the jet nozzle outletfrom the boat, a drive shaft arranged to be driven by a motor mounted inthe boat and said drive shaft extending into said stator housing, adriving bevel gear mounted on said drive shaft within said statorhousing, an impeller shaft mounted in said stator housing and extendingin the direction of flow between the inlet end and the outlet end ofsaid stator housing, a driver bevel gear positioned on said impellershaft and arranged to be driven by said driving bevel gear, wherein theimprovement comprises first bearing means provided within said statorhousing for rotatably supporting said impeller shaft and second bearingmeans provided within said stator housing for rotatably supporting saiddrive shaft, said first bearing means comprises a pair of spaced firstbearing members mounted on said impeller shaft, each on an opposite sideof said driver bevel gear, and said second bearing means comprises apair of second bearing members mounted on said drive shaft, each on anopposite side of said driving bevel gear, said stator housing comprisesan annular-shaped inner shell and an annular-shaped outer shellencircling and spaced outwardly from said inner shell, said inner andouter shells defining therebetween an annular flow passage through saidstator housing, a tubular-shaped projection secured to and extendingoutwardly from said outer shell and forming an opening through saidouter shell for said drive shaft, one of said second bearing membersmounted in said projection, a bearing frame supported within said innershell, a projection attached to said bearing frame, and the other one ofsaid second bearing members mounted in said projection on said bearingframe and positioned between said driving bevel gear on said drive shaftand said impeller shaft, said inner and outer shells each have anopening therethrough in alignment with said tubular-shaped projectionson said outer shell and located on the opposite side of said statorhousing from said tubular-shaped projections, and a removable insertpositioned in the openings in said inner and outer shells and forming awater-tight scaled closure therefor, said insert shaped to conform tothe configuration of said inner and outer shells forming said statorhousing.

1. A water jet drive mounted inboard in a speed boat which has a water inlet in the bottom of the boat and a jet nozzle outlet in the stern of the boat, comprising a stator housing positioned in the boat and forming an annular flow passage and having an inlet end connected to the water inlet into the boat and an outlet end connected to the jet nozzle outlet from the boat, a drive shaft arranged to be driven by a motor mounted in the boat and said drive shaft extending into said stator housing, a driving bevel gear mounted on said drive shaft within said stator housing, an impeller shaft mounted in said stator housing and extending in the direction of flow between the inlet end and the outlet end of said stator housing, a driver bevel gear positioned on said impeller shaft and arranged to be driven by said driving bevel gear, wherein the improvement comprises first bearing means provided within said stator housing for rotatably supporting said impeller shaft and second bearing means provided within said stator housing for rotatably supporting said drive shaft, said first bearing means comprises a pair of spaced first bearing members mounted on said impeller shaft, each on an opposite side of said driver bevel gear, and said second bearing means comprises a pair of second bearing members mounted on said drive shaft, each on an opposite side of said driving bevel gear, said stator housing comprises an annular-shaped inner shell and an annular-shaped outer shell encircling and spaced outwardly from said inner shell, said inner and outer shells defining therebetween an annular flow passage through said stator housing, said inner shell having a first end directed toward the inlet end of said stator housing, and a second end directed toward the outlet end of said stator housing, said impeller shaft extending through the first end of said inner shell, an impeller mounted on said impeller shaft between the inlet end of said stator housing and the first end of said inner shell, a bearing flange mounted in the first end of said inner shell, one of said first bearing members supported in said bearing flange, the other one of said first bearing members supported directly in the second end of said inner shell, a two-part bell-like member attached to the second end of said inner shell and forming a closure over the second end of said inner shell, said two-part bell-like member comprises an inner bell dome attached to the second end of said inner shell and projecting therefrom toward the outlet end of said inner housing, said inner bell dome having a centrally positioned extension extending toward the outlet end of said stator housing, and an outer bell dome concentrically arranged about said inner bell dome and detachably secured to said centrally pOsitioned extension on said inner bell dome.
 2. A water jet drive mounted inboard in a speed boat which has a water inlet in the bottom of the boat and a jet nozzle outlet in the stern of the boat, comprising a stator housing positioned in the boat and forming an annular flow passage and having an inlet end connected to the water inlet into the boat and an outlet end connected to the jet nozzle outlet from the boat, a drive shaft arranged to be driven by a motor mounted in the boat and said drive shaft extending into said stator housing, a driving bevel gear mounted on said drive shaft within said stator housing, an impeller shaft mounted in said stator housing and extending in the direction of flow between the inlet end and the outlet end of said stator housing, a driver bevel gear positioned on said impeller shaft and arranged to be driven by said driving bevel gear, wherein the improvement comprises first bearing means provided within said stator housing for rotatably supporting said impeller shaft and second bearing means provided within said stator housing for rotatably supporting said drive shaft, said first bearing means comprises a pair of spaced first bearing members mounted on said impeller shaft, each on an opposite side of said driver bevel gear, and said second bearing means comprises a pair of second bearing members mounted on said drive shaft, each on an opposite side of said driving bevel gear, said stator housing comprises an annular-shaped inner shell and an annular-shaped outer shell encircling and spaced outwardly from said inner shell, said inner and outer shells defining therebetween an annular flow passage through said stator housing, a tubular-shaped projection secured to and extending outwardly from said outer shell and forming an opening through said outer shell for said drive shaft, one of said second bearing members mounted in said projection, a bearing frame supported within said inner shell, a projection attached to said bearing frame, and the other one of said second bearing members mounted in said projection on said bearing frame and positioned between said driving bevel gear on said drive shaft and said impeller shaft, said inner and outer shells each have an opening therethrough in alignment with said tubular-shaped projections on said outer shell and located on the opposite side of said stator housing from said tubular-shaped projections, and a removable insert positioned in the openings in said inner and outer shells and forming a water-tight sealed closure therefor, said insert shaped to conform to the configuration of said inner and outer shells forming said stator housing. 